Mesoscale Discussion 914

Issued

Jun 10, 2021, 7:30 PM MDT (01:30 UTC)

Expired

Jun 10, 2021, 9:30 PM MDT

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Tornado watch 251

Counties Daniels County, MT, Richland County, MT, Roosevelt County, MT, Sheridan County, MT, Wibaux County, MT, Billings County, ND, Burke County, ND, Divide County, ND, Golden Valley County, ND, McKenzie County, ND, Mountrail County, ND, Williams County, ND

The Glasgow radar (KGGW), 202 km from the middle of the area, began a volume at 01:31 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

• Severe Thunderstorm Watch 254Jun 10, 8:50 PM MDT

706 
ACUS11 KWNS 110131
SWOMCD
SPC MCD 110130 
NDZ000-MTZ000-110330-

Mesoscale Discussion 0914
NWS Storm Prediction Center Norman OK
0830 PM CDT Thu Jun 10 2021

Areas affected...Western North Dakota

Concerning...Tornado Watch 251...

Valid 110130Z - 110330Z

The severe weather threat for Tornado Watch 251 continues.

SUMMARY...The severe threat continues for WW 251. The greatest
near-term tornado risk will likely persist across west-central ND
were training embedded supercells may continue. Developing
convection across northeast MT may pose a tornado risk, but
confidence is somewhat low.

DISCUSSION...Thunderstorms that initially developed across far
eastern MT have only gradually moved into west/northwest ND over the
past 1-2 hours. This is largely due to meridional flow aloft and
weak synoptic forcing (the main cold front remains displaced to the
west). This has resulted in a broken line of training convection
from near KD50 in northwest ND to near KGDV in eastern MT. Although
low-level shear remains very favorable for a tornado threat across
northwest ND (as noted by high 0-1 km SRH values in the KMBX VWP),
training stratiform and convective precipitation has cooled surface
temperatures and reduced low-level lapse rates. This may hinder the
potential for surface-based convection and the overall tornado
threat to some degree (though severe hail/wind remain possible). 

Further south in west-central ND, persistent warm/moist advection
into the southern end of the line is supporting embedded supercells
that have produced tornadoes over the past 2 hours. 100-200 m2/s2
ESRH (per RAP mesoanalysis) near the surface warm front will
continue to support the tornado threat in the near term. Gradual
cold pool amalgamation along the line and interactions with
convection emerging from the west/southwest out of central MT should
limit the tornado potential after 03 UTC. 

Developing convection is noted along a surface trough/remnant
outflow boundary across northeast MT. Favorable instability and
low-level shear along and immediately to the east of the boundary
may support a small corridor for a tornado threat, but cooler
temperatures closer to the ND border and storm interactions
introduce uncertainty for this potential.

..Moore.. 06/11/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...BIS...BYZ...GGW...

LAT...LON   46650445 47150450 47740467 48010593 48810605 49150578
            49160350 49150244 49030207 48360226 47550271 46960302
            46580348 46470414 46650445

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The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.